LoadImageIntoTexture Runtime Change

Hey,

I'd like to create a script that assigns a texture loaded from the web to three different walls and the url should be changeable within a textfield, so that it changes the texture as well. What I have so far is that it assigns the texture of the predefined url but when I change the url in the textfield, somehow it only changes the texture of one wall. What should I do that it assigns the texture of the new link to every wall? Where's the problem and is there maybe a better solution for what I want to do?

PS: I have just a basic scene with three walls called WallR, WallT and WallL. The "user" should be able to put any link there with an image (ofc with the right format) so it's not possible to preload every texture.

Thank you in advance, Opak

 var url = "http://www10.pic-upload.de/28.05.13/2mztreb6f16.jpg";
 var wallL : GameObject;
 var wallR : GameObject;
 var wallT : GameObject;
 
 function Start () {
     wallL = GameObject.Find("WallL");
      wallR = GameObject.Find("WallR");
      wallT = GameObject.Find("WallT");
      
 // Create a texture in DXT1 format
         renderer.material.mainTexture = new Texture2D(4, 4, TextureFormat.DXT1, false);
         while(true) {
             // Start a download of the given URL
             var www = new WWW(url);
             // wait until the download is done
             yield www;
             // assign the downloaded image to the main texture of the object
             www.LoadImageIntoTexture(renderer.material.mainTexture);
             wallL.renderer.material.mainTextureScale = Vector2 (1 , 0.33);
             wallT.renderer.material.mainTextureScale = Vector2 (1 , 0.33);
             wallT.renderer.material.mainTextureOffset = Vector2 (1 , 0.335);
             wallR.renderer.material.mainTextureScale = Vector2 (1 , 0.33);
             wallR.renderer.material.mainTextureOffset = Vector2 (1 , 0.67);      
         }    
 }
 
 function Update () {
 
 }
 
 function OnGUI () {
     url = GUI.TextField (Rect (10, 10, 500, 20), url, 100); 
 }